1. Field of the Invention
This invention relates generally to reciprocating piston type internal combustion (I.C.) engines. More specifically it relates to such an I.C. engine in which the axes of the pistons do not intersect, i.e. are geometrically offset from, the crankshaft axis.
2. Background Information
Certain technology relating to reciprocating piston I.C. engines in which the crankshaft axis is offset from the piston-cylinder axes is described in U.S. Pat. Nos. 810,347; 2,957,455; 2,974,541; 4,628,876; and 4,945,866; in Japan patent document 60-256,642; in Soviet Union patent document 1551-880-A; and in JSAE Conference proceedings 966, 1996-10. According to descriptions contained in those publications, the various engine geometries are motivated by various considerations, including power and torque improvements and friction and vibration reductions.
A production V-type engine in which the crankshaft axis is offset from the piston-cylinder axes is the Volkswagen narrow V engine, which has six cylinders and a 15.degree. V, and is known as the VR6 engine. Because a 15.degree. V is quite narrow for a V-type engine, it is believed that a reason for offsetting the crankshaft axis is to control the height of the engine.
In-line, or straight, engines in which the crankshaft axis is offset from the piston axes were used in early twentieth century racing engines.